Insights into alleviating high brittleness of TiCu compound by doping C and O as interstitials: First-principle calculations

The highly brittle TiCu compound poses a significant threat to the reliability of Ti/Cu composite components, imposing limitations on their widespread application. In this work, a promising method for alleviating the brittleness of TiCu compounds through the introduction of interstitial carbon (C) a...

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Bibliographic Details
Main Authors: Yujie Tao, Yibo Liu, Yue Liu, Qi Sun, Haoyu Kong, Qingjie Sun
Format: Article
Language:English
Published: Elsevier 2025-01-01
Series:Next Materials
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Online Access:http://www.sciencedirect.com/science/article/pii/S2949822824001989
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Summary:The highly brittle TiCu compound poses a significant threat to the reliability of Ti/Cu composite components, imposing limitations on their widespread application. In this work, a promising method for alleviating the brittleness of TiCu compounds through the introduction of interstitial carbon (C) and oxygen (O) atoms was explored and investigated. Seven different doping models were tested to determine the optimal concentration of C and O, with a comprehensive analysis of their impacts on the phase stability, mechanical properties, and electronic structure of TiCu conducted via first-principle calculations. The results demonstrate that O increases the thermodynamic stability of TiCu but adversely affects its mechanical stability, while C exerts the opposite effect. An appropriate ratio of C and O atoms has the potential to improve comprehensive mechanical properties. Concurrent doping C and O expands the stable concentration range, with TiCu-1 C, TiCu-4 O, and TiCu-2C2O exhibiting both remarkable thermodynamic and mechanical stability. While the [0 0 1] orientation displays increased bulk deformation resistance after doping, apparent decreases in the B and E values are observed for other orientations. Furthermore, compared to undoped TiCu, a maximum reduction of 78.8 % for G value is observed for C/O-doped TiCu, indicating enhanced dislocation slip and plastic deformation ability. Charge transfer is also influenced by C and O interstitials, resulting in increased charge density around C and O atoms and a notable decrease in the charge transfer quantity of Ti and Cu. This weakens the covalency of Ti-Cu bonds, thereby contributing to improved ductility through reduced deformation resistance and weaker covalent bonds.
ISSN:2949-8228